X-Git-Url: http://www.aleph1.co.uk/gitweb/?p=yaffs2.git;a=blobdiff_plain;f=yaffs_guts.c;h=d067d1d03d53552efbff6d9bd16e84f83a86f71d;hp=087ac958f61f127a9c9d8c99a89d1b5e71d70fb5;hb=af9db26a2299dc67c364d9f65d8c3758560a7ff0;hpb=b3c7045d1ba097d7669f9b5cf4d2a6800e7ac30d

diff --git a/yaffs_guts.c b/yaffs_guts.c
index 087ac95..d067d1d 100644
--- a/yaffs_guts.c
+++ b/yaffs_guts.c
@@ -1,7 +1,7 @@
 /*
  * YAFFS: Yet Another Flash File System. A NAND-flash specific file system.
  *
- * Copyright (C) 2002-2007 Aleph One Ltd.
+ * Copyright (C) 2002-2010 Aleph One Ltd.
  *   for Toby Churchill Ltd and Brightstar Engineering
  *
  * Created by Charles Manning <charles@aleph1.co.uk>
@@ -10,10 +10,6 @@
  * it under the terms of the GNU General Public License version 2 as
  * published by the Free Software Foundation.
  */
-
-const char *yaffs_guts_c_version =
-    "$Id: yaffs_guts.c,v 1.120 2010-03-15 23:10:34 charles Exp $";
-
 #include "yportenv.h"
 #include "yaffs_trace.h"
 
@@ -37,8 +33,17 @@ const char *yaffs_guts_c_version =
 /* Note YAFFS_GC_GOOD_ENOUGH must be <= YAFFS_GC_PASSIVE_THRESHOLD */
 #define YAFFS_GC_GOOD_ENOUGH 2
 #define YAFFS_GC_PASSIVE_THRESHOLD 4
+
 #define YAFFS_SMALL_HOLE_THRESHOLD 3
 
+/*
+ * Checkpoints are really no benefit on very small partitions.
+ *
+ * To save space on small partitions don't bother with checkpoints unless
+ * the partition is at least this big.
+ */
+#define YAFFS_CHECKPOINT_MIN_BLOCKS 60
+
 #include "yaffs_ecc.h"
 
 
@@ -183,7 +188,7 @@ static __u32 ShiftsGE(__u32 x)
 
 static __u32 Shifts(__u32 x)
 {
-	int nShifts;
+	__u32 nShifts;
 
 	nShifts =  0;
 
@@ -2956,10 +2961,17 @@ static int yaffs_FindBlockForAllocation(yaffs_Device *dev)
 
 
 
+static int yaffs_CheckpointRequired(yaffs_Device *dev)
+{
+	int nblocks = dev->internalEndBlock - dev->internalStartBlock + 1 ;
+	return dev->param.isYaffs2 &&
+		!dev->param.skipCheckpointWrite &&
+		(nblocks >= YAFFS_CHECKPOINT_MIN_BLOCKS);
+}
 static int yaffs_CalcCheckpointBlocksRequired(yaffs_Device *dev)
 {
 	if (!dev->nCheckpointBlocksRequired &&
-	   dev->param.isYaffs2) {
+		yaffs_CheckpointRequired(dev)){
 		/* Not a valid value so recalculate */
 		int nBytes = 0;
 		int nBlocks;
@@ -4880,7 +4892,7 @@ static int yaffs_WriteCheckpointData(yaffs_Device *dev)
 {
 	int ok = 1;
 
-	if (dev->param.skipCheckpointWrite || !dev->param.isYaffs2) {
+	if (!yaffs_CheckpointRequired(dev)) {
 		T(YAFFS_TRACE_CHECKPOINT, (TSTR("skipping checkpoint write" TENDSTR)));
 		ok = 0;
 	}
@@ -5136,8 +5148,6 @@ int yaffs_DoWriteDataToFile(yaffs_Object *in, const __u8 *buffer, loff_t offset,
 	dev = in->myDev;
 
 	while (n > 0 && chunkWritten >= 0) {
-		/* chunk = offset / dev->nDataBytesPerChunk + 1; */
-		/* start = offset % dev->nDataBytesPerChunk; */
 		yaffs_AddrToChunk(dev, offset, &chunk, &start);
 
 		if (chunk * dev->nDataBytesPerChunk + start != offset ||
@@ -5147,7 +5157,7 @@ int yaffs_DoWriteDataToFile(yaffs_Object *in, const __u8 *buffer, loff_t offset,
 			   TENDSTR),
 			   (int)offset, chunk, start));
 		}
-		chunk++;
+		chunk++; /* File pos to chunk in file offset */
 
 		/* OK now check for the curveball where the start and end are in
 		 * the same chunk.